Chris Hemsworth explains that bulging bicep shot: 'Photoshop, lighting and certain angles'

Chris Hemsworth's out-of-control bicep almost broke the internet back in January, but according to the buff star, it wasn't just muscle we were gawping at.

Appearing on The Project, the 32-year-old had a hilarious take on the Instagram picture, posted by his brother Luke.

Why was one arm bigger than the other? Was it the Thor hammer arm? Chris answers it all with that laconic sense of humour we've come to love. Watch above!

The Aussie actor is back on our shores, stepping out as the new international brand ambassador for TAG Heuer at an exclusive event at Sydney's Royal Botanic Gardens overnight.

FYI, his muscles were contained in a suit. But we're sure we'll see those biceps again soon.

That photo, once again:

Model Jessica Gomes and Chris Hemsworth at the TAG Heuer event on February 4. Image: Getty.